This is why a motorcycle chain keeps getting looser

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A motorcycle chain is an important element to the machine; without it, you wouldn’t be able to move your motorcycle much. Even though it is important to maintain it, it can become frustrating. Many people have the issue of their chain getting loose all the time without any solid explanation.

Why is my motorcycle chain always getting loose? Rear axle problems or loosening of the chain tensioning bolts can often cause a motorcycle’s chain to get loose. A worn-out or worn-down sprocket tooth, too tight a tension, or the wrong size chain can all lead to loosening of the chain.

It’s important to fix the issue if you are constantly running into a loose chain on your motorcycle. Having run into this problem many times myself, I can explain everything you need to know about finding the reason it’s becoming loose and how to stop it from happening again.

Why a Loose Chain?

There are many reasons why a motorcycle chain could become detached repeatedly. There are a few simple ways to check how it’s happening that shouldn’t take much time at all.

The ability to move will cause a new bike chain to become loose at first. “stretch” A little. It’s not the metal itself that stretches, rather in between the links there’s a little bit of slack. As those links turn, they wear into each other; they’re brand new and the metal isn’t quite worn in yet.

It is extremely rare for each link to wear. But because there’s an average of about 100 links in a chain, all of that wear combined can give the impression that the chain has stretched and you’ll likely notice some slack on your new chain after a few hundred miles. You should ride your new chain for 50 miles before you check its tension. You can tighten it up if necessary.

If you haven’t recently gotten a new chain and you notice it still becoming loose, there is one common culprit (especially among older motorcycles). The rear axle slides through two fork-shaped parts on the swing arm that point backwards. The axle is located in the middle between these two forks.

You will find a bolt to the rear of the wheel. When you tighten it, it pulls back the rear tire. If your chain is slipping, it could be a sign that the axle tensioning bolts or chain are too loose. This is 90% of the reason for a loose chain.

A worn-down front or rear sprocket, or both, can cause a loose chain. Since there’s less surface area going in between the links to spread them out, the chain will appear to have become stretched. It is usually a temporary problem, but it is worth looking at the teeth of your sprockets if you notice this happening.

Each chain has a certain amount of flexibility. That’s why it’s important to check the tension of the chain to ensure it isn’t too tight. If you’re over tightening the chain, the chain is going to keep “stretching,” Wear the links more aggressively. Check with your owner’s manual and make sure you aren’t over tightening your chain as every motorcycle is different with how much tension it needs.

Motorcycle chains cannot be interchangeable. To fit a motorcycle, a particular type and size of chain is required. The chain must fit over each tooth of the sprocket. If it doesn’t fit perfectly with the sprocket teeth (such as if any of the links sit on top of the teeth), you have the wrong chain.

This is a problem I’ve personally seen. Once I bought a chain from eBay and it had the wrong spacing for the sprocket. It fit around almost 3/4 of the sprocket with just a few teeth that didn’t fit between the links. Replace your chain if you notice any of these problems. This could cause the chain to fall off completely.

How to fix a loose chain

It is easy to fix a loose chain on a motorcycle, even for those with little experience. Once you’ve found the reason your chain keeps getting loose, try one of the following methods to fix it.

If your new chain is still loose after 50 miles, you can ride 50 more miles to tighten it. Each chain is unique, so it might take several hundred miles to get there. “stretch” into it’s normal state. There’s a lot of play in the rear chain adjustment so even if your chain is still working on wearing into those links, you’ll have room to add more tension.

Your likely culprit, though, is that the rear axle or tensioning bolts aren’t tight enough. These bolts have to be torqued to a certain tightness, so again you’ll need to refer to your owner’s manual to see exactly how tight the axle and bolts need to be.

Sometimes the motorcycle’s constant vibration can cause the tensioning bolts to become loose, which can lead to slack in your chain. If your motorcycle vibrates a lot, you might try to put a lock nut there to keep them from coming loose.

You’ll obviously need to replace one or both of the sprockets if you’ve notice the teeth have worn down. Even if it’s just a few teeth that have worn, that can create a ripple affect and cause the other teeth to wear down much faster, so it’s best to simply replace it.

If you have tried all of these methods and your chain still seems too loose, it may be time to buy a new chain because it’s probably worn and stretched too much. It is quite simple to change a chain.

On most chains, there’s one link on it called a master link. There’s a little clip on there that you have to pop out and will make the chain separate. The front sprocket is pretty hidden, but there’s usually a few teeth exposed that you can feed the new motorcycle chain on to which will come out the other side when rotated. After you have inserted the sprocket, you can attach the master link to the chain by attaching the clip.

If you have a motorcycle that does not have a master link, you’ll have to cut the chain off with either a grinder or you can take the rear wheel off. You’ll need to take the rear wheel off to put the new one on anyway.

An entire video series has been created about how to repair a motorcycle. This series contains detailed tutorials on how to remove, replace, and adjust the tension of your chain. You will also find tutorials for difficult parts such as the body, carb rebuilds, or electrical. Click here for more information if you’re interested in restoring or building your dream motorcycle!

Maintenance and Prevention

A motorcycle chain that is constantly coming apart can be very frustrating. It is important to perform regular maintenance on your motorcycle chain to prevent it from becoming an annoying problem.

Once you have fixed your chain, it’s important to continue checking it every few hundred miles to make sure it still isn’t becoming loose. You can check it every other time that you fill up with gasoline.

You must ensure that the tension is right. Every motorcycle has a different tension requirement, but most bikes need about a quarter inch of slack. But again, check in your owner’s manual to check how much slack your specific motorcycle needs on it’s chain.

You should lubricate the chain every 4,000 to 5,000 miles, or every six month, depending on which comes first. Since oil changes are at roughly the same time, I make sure to check my chain.

Consequences of a loose chain

Loss of chain can cause the entire sprocket to come off. This means you’ll lose power to your motorcycle even though the engine is still running. This might not seem like a big deal if you consider losing power on the freeway.

A loose chain also has the potential of breaking and either slapping the back of the rider’s leg or projecting backwards and damaging the vehicles behind. Or it’s possible for it to jam up in one of the sprockets and cause the motorcycle to abruptly stop. Check out my article to find out what happens if your motorcycle chain is broken.

It is crucial to pay attention to your motorcycle’s chain. It’s a small and simple part, but if left unchecked it can be quite a nuisance for the motorcycle owner.

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